On-site electric motor start-up diagnostic tool

ABSTRACT

A diagnostic tool may be attached to the control panel of a piece of machinery within a plant or factory which includes an electric motor. The diagnostic tool includes indicators for providing information to an operator of the equipment for which the control panel provides power. These indicator inform the operator of various modes of operation of the control circuitry within the control panel which regulate the power going to the motor. In this manner, the operator may determine if the machinery is ready to run, and if not, if it is necessary to call a technician.

BACKGROUND OF THE INVENTION

1. FIELD OF THE INVENTION

The present invention relates to diagnostic tools for trouble shootingelectric motor start-up control circuitry. More particularly, thepresent invention relates to such a diagnostic tool which is permanentlyinstalled to the motor start-up control panel so as to provideindications of the status of the electric motor and simple instructionsfor the most general and common troubleshooting techniques to anoperator of the device, without the need of a technician.

2. DESCRIPTION OF THE PRIOR ART

U.S. Pat. No. 2,241,589 issued May 13, 1941 to Cyril P. Feldhausendiscloses a controller for motor driven printing presses which alertsusers around the press that a motor is about to start up. The firstdepression of a start switch causes an alarm to be activated. The seconddepression of a start switch disengages that alarm and activates a motorto run the press.

U.S. Pat. No. 3,179,930 issued April 20, 1965 to Eric Pell discloses acircuit condition indicating system having a plurality of faultindicators, each one connected across an overload contact to indicatewhen that contact opens.

U.S. Pat. No. 3,531,791 issued Sep. 29, 1970 to Richard C. Wellsdiscloses a remote indicating and control device to provide remotecontrols over a machine and indications of the status of operation ofthe machine.

U.S. Pat. No. 3,999,176 issued Dec. 21, 1976 to Walter J. Kellogdiscloses an indicator light circuitry for indicating normal operationwhen the light is continuously on, an emergency condition when the lightis flashing off and on, another condition when the light is flashingbetween a dim and bright status, and an off condition.

U.S. Pat. No. 4,167,003 issued Sep. 4, 1979 to Benny W. Stansburydiscloses a device for monitoring equipment failures within a planthaving sensors at various parts of the plant and digital circuitry forcontrolling various indicators.

None of the above inventions and patents, taken either singly or incombination, is seen to describe the instant invention as claimed.

SUMMARY OF THE INVENTION

The on-site electric motor diagnostic tool of the present inventionallows the operator within a plant or factory to troubleshoot thesimplest most common failures associated with starting an electricmotor, thereby reducing the number of times a technician has to becalled to troubleshoot the problem. In general, factories and plants usethree-phase electric motors to power assembly line conveyers, aircompressors, and other machinery. Each electric motor generally includesits own control panel having at least a motor start-up relay, overloadblock protection associated with the motor start-up relay, and a fusebox or circuit breaker circuitry.

Connected to the control panel are a plurality of remote start/stopswitches generally located in close proximity to the electric motor andmachinery associated therewith. If the operator presses the start buttonfor the machinery and the machinery fails to operate, the operator maygo to the control panel and reset the circuit breaker and overloadprotection block to correct the problem. Once doing this and proceedingback to the machinery to try and start it again, if the machinery stillfails to start, the operator generally calls a technician to troubleshoot the machinery.

The diagnostic tool of the present invention connects to the controlpanel of an electric motor so as to give simple indications to theoperator when the unit is running, when the unit is ready to run, whenone or more of the plurality of remote stop switches may be stuck open,when the overload block has been triggered, and when a fuse is blown orcircuit breaker circuit needs to be reset.

Accordingly, it is a principal object of the invention to provide adiagnostic tool attachable to an electric motor start-up control panelfor providing indications of the problem of the electric motor start-upcontrol circuitry located therein.

It is another object of the invention to eliminate the necessity ofhaving the operator calling the technician in simple cases where theoperator could solve the problem.

It is a further object of the invention to provide the necessary visibleindications to the operator of when the machinery will start or isalready running.

It is still a further object of the invention to provide improvedelements and arrangements thereof in a diagnostic apparatus for thepurposes described herein which is inexpensive, simple to connect toexisting control panels, dependable, and fully effective inaccomplishing its intended purposes.

These and other objects of the present invention will become readilyapparent upon further review of the following specification anddrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an environmental electrical schematic diagram of the presentinvention.

FIG. 2 is a front view of the diagnostic tool of the present invention.

FIG. 3 is an environmental view of the device of the present inventionattached to a control panel with control panel door closed.

FIG. 4 is an environmental view of the device of the present inventionattached to a control panel with the control panel door opened.

Similar reference characters denote corresponding features consistentlythroughout the attached drawings.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The on-site electric motor start-up diagnostic tool 1 is attached to anelectric motor start-up control panel 3, as illustrate in FIGS. 1 and 3.A typical motor start-up control circuit 5 found within an electricmotor start-up control panel 3 having the diagnostic tool attachedthereto is illustrated in FIG. 1. The circuit is typical for mostelectric motor start-up control panels used in industry. The circuitincludes a three-phase 480 volt power supply breaker connected in serieswith a motor relay 9 and the three-phase electric motor 13. Atransformer 15 is used to tap-off some electrical power from one pair ofthe three-phase power lines 16. This electrical power is used toenergize the motor relay coil 11 under the control of a plurality ofremote switches 17.

The transformer 15 provides an auxiliary power source of regularhousehold voltage, e.g., 120 volts. This voltage potential is placedacross a positive line L1 and a negative line L2. An auxiliary shut downswitch 19 and a start/stop controller having a start-up switch 33 and astop switch 30 are located at a remote location from the motor start-upcontrol panel 3. A motor relay controller conduction path extends acrossthe positive and negative power lines L1 and L2 providing power from theauxiliary power source to the auxiliary shut down switch 19 and theremote start/stop controller 21. The motor relay coil 11 is alsoprovided within the conduction path along with the contacts 27 of anoverload protection block 29 incorporated within the motor start-uprelay 9.

The start/stop controller 21 is provided to the operator of themachinery utilizing the electric motor 13 allowing the operator tostart-up the machinery or shut the machinery down. The auxiliaryshut-down switch 19 in series with the remote start/stop controller isgenerally part of a shut-down sensor incorporated within the machineryto detect a condition which may become dangerous in which the machineryshould not be operated. If the shut-down sensor detects such a dangerouscondition, the auxiliary shut-down switch 19 is opened, breaking theflow of electrical power within the conduction path, thereby shuttingdown the electric motor 13 as described below. The particular shut-downsensor utilized in the machinery, both not illustrated, is dependent onthe type of machinery used and the particular condition the sensor ismonitoring. Neither form a part of the present invention. The diagnostictool 1 of the present invention may be utilized by any machinery used ina plant or factory having an electric motor 13 and control panel 3.

As stated above, FIG. 1 illustrates the electric motor start-upcircuitry 5 found in a typical control panel 3 used in industryutilizing an auxiliary power source which tapes off some of the powerprovided to the motor 13 to control the starting up and shutting down ofthe motor 13. If power flows through the conduction path, the relay coil11 is energized, thereby closing the motor relay contacts 25. With themotor relay contacts 25 closed, the three phase electric power comingfrom the breaker circuit 7 travels through the motor relay contacts 25and powers the motor 13. The motor relay coil 11 also causes the seal-incontact 31 to close. The seal-in contact 31 is in parallel with theremote start switch 33 so that the operator may release the start switch33 after the motor relay coil 11 has been energized, allowing thenormally open start switch 33 to open again with the power flowingthrough the conduction path going through the seal-in contact 31 insteadof the start switch 33.

Once the machinery is running as power is being provided to the electricmotor 13, the machinery may be shut-down by the breaker circuit 7 in theevent of a power surge occurring across the three-phase power lines 18going into the breaker 7. A fuse 35 is also provided within theconduction path to prevent such a power surge from damaging the motorrelay coil 11. If the fuse 35 is blown, the motor relay coil 11 remainsde-energized and the motor relay contacts 25 are opened, therebyshutting down the motor 13. In this manner, the electric motor 13 isprotected against damage which may occur during a power surge across thepower lines 18.

The breaker 7 protects the motor 13 from power surges, but does notprotect the motor 13 from a gradual rise in current drain from the powerlines 16 which may damage the electric motor 13 by causing it to exceedits recommended maximum output power rating which, over a period oftime, would eventually result in the failure of the electric motor 13.To prevent such damage, the starter relay 9 is provided with an overloadprotection block 29. This includes three resistive heater coils 37, eachone located within one line of the three-phase power lines 16, and eachone producing a predetermined amount of heat for the normal amount ofload current passing across the three power lines 16 when the motor 13is in operation. The overload block circuit 29 also includes threenormally closed overload block contacts 27 located within the conductionpath, each overload block contact 27 being associated with one of theoverload block resistive heater coils.

Should one or more of the heater coils 37 produce a greater amount ofheat than the predetermined amount of heat due to an amount of currentpassing therethrough being greater than normal, the overload block 29will not be able to dissipate this additional heat which will eventuallybuild up and cause the each affected resistive heater coil 37 to heat upto a point such that the overload block contact 27 associated therewithwill open. Since each of the overload block contacts 27 are in serieswith one another within the conduction path, should any one of themopen, the conduction path is blocked causing the motor relay coil 11 tode-energize and the motor relay contacts 25 as well as the seal-incontact 31 to open. The motor 13 is shut-down once the motor relaycontacts 25 are opened, thereby preventing the motor 13 from beingdamaged by the excessive prolonged load currents supplied by one or moreof the power lines 16.

If the operator is unable to start-up the machinery, the breaker circuit7 may need to be reset, the overload protection block 29 may need to bereset, the fuse 35 may need to be replaced, the auxiliary shut downswitch 19 may have been triggered and the condition which triggered theswitch would have to be corrected, or the remote start/stop controller21 used by the operator may have an open wire or contact. In general,when the operator is unable to restart the machine after resetting thecircuit breaker 7 and the overload protection block 29, the operatorcalls for a technician to trouble shoot the problem. This results inmore down time for the machinery and the extra man hours for thetechnician to trouble shoot the problem.

The diagnostic tool 1 of the present invention is not intended toilluminate the need for a technician, but is intended to reduce thenumber of times a technician has to be called by informing the operatorof any actions which can be taken by him or her in order to correct theproblem. If the operator can solve the problem, the machinery is up andrunning quicker than if a technician has to troubleshoot the problem.

As illustrated in FIG. 2, the diagnostic tool 1 of the present inventionis a four light display to indicate to the operator when the unit isrunning, when the unit is ready to run, when one or more of theplurality of remote stop switches may be stuck open, when the overloadblock has been triggered, and when a fuse is blown or circuit breakercircuit needs to be reset. In the example shown in FIG. 2, each of thelamps 38, 39, 40, and 41 are on indicating the that the associatedmachinery is running.

A control panel door 43 having the diagnostic tool 1 of the presentinvention attached thereto is illustrated in FIG. 3. The control panel43 already allows the operator to determine whether or not the breakercircuit 7 has been thrown and also allows the operator to reset theoverload block through the use of a reset button 45. Generally, a window47 is provided on the control panel to allow the operator to determinewhether or not the breaker 7 needs to be reset. However, if the operatorresets the breaker 7 and pushes the overload protection block resetbutton, and then returns to the machinery only to find it still will notstart, the operator can not know why the machinery will not run since noindications are provided by the control panel 3 of the status of thestart-up control circuitry 5 located therein. The diagnostic tool 1 ofthe present invention corrects for this deficiency.

The diagnostic tool 1 provides an indication to the operator of thestatus of the motor start-up control circuitry 5 within the controlpanel 3. As illustrated in FIG. 3, should the operator at the controlpanel 3 press the overload reset button 45 and the first three lamps 38,39, and 40 from the top remain on, the operator knows that the machinerywill operate once the start button 33 is pressed. As stated above, theremote start/stop controller 21 is located near the machinery, while thecontrol panel 3 is generally located within a motor control centerhaving a plurality of control panels associated therewith, each controlpanel providing power to a separate piece of machinery, not illustrated.When the operator has to go to the control panel 3 of the machinerywhich will not start, it would save the operator time to know whether ornot after resetting the breaker 7 and overload block circuit 29, whetherthe machinery will run once the operator returns to the machinery andattempts to start it up.

The other codes provided by the diagnostic tool 1 to indicate the statusof the control circuitry is illustrated in FIG. 2. For example, if thefirst lamp 38 and the third lamp 40 are on, the operator knows that atleast one of the overload block contacts 27 are open and that theoverload protection block 29 needs to be reset. As stated above, theoverload contacts 27 are opened when the resistive heater coil 37associated therewith has reached a temperature greater than apredetermined temperature. Unless the overheated resistive coils 37 areallowed time to cool down, pressing the reset button will not reset thecontacts associated therewith. However, the diagnostic tool 1 of thepresent invention allows the operator to know whether the action takenby him or her has had an effect in correcting the problem before he orshe returns to the machinery to in an attempt to start it up again.

If all of the lamps 38, 39, 40 are on, as illustrated in FIG. 2, theoperator knows that if the start button 33 is pushed the machinery willstart. However, if none of the lamps 38, 39, 40, and 41 are on, theoperator knows that the breaker circuit 7 needs to be reset or the fuse35 needs to be replaced. If the first two lamps 38 and 39 are on, eitherthe auxiliary shut-down switch 19 is opened or the remote start/stopcontroller 21 has an open circuit located therein.

The on-site diagnostic tool 1 of the present invention is connected tothe circuitry 5 of a control panel 3 as illustrated in FIG. 1. Asillustrated in FIG. 3, and discussed further below, the housing of thediagnostic tool 1 is attached to the door 43 of the control panel 3readily visible to the operator. The housing of the diagnostic tool 1contains the lamps 38, 39, 40, 41 and an optional alarm relay circuit 49as illustrated in FIG. 1. The housing of the diagnostic tool 1 includesfive electrical wire connections extending outward therefrom attached tothe electric motor start-up control circuitry 5.

A first wire connection 51 of the diagnostic tool 1 of the presentinvention is connected to the electric motor start-up control circuitrybetween the fuse 35 and the auxiliary shut-down switch 19. A second wireconnection 52 is attached between the stop switch 30 and the startswitch 33. A third wire connection 53 is attached between the seal-incontact 31 and the motor relay coil 11. A fourth wire connection 54 isattached between the motor relay coil 11 and the overload contacts 27. Afifth wire connection 55 is connected between the overload contacts 27and the negative line L2. The five wire connections of the device 1 areeach connected at various points within the conduction path as describedabove in the control panel 3. In this manner, each of the wireconnections 51, 52, 53, and 54 are used by the device 1 to indicatewhere power is present or absent within the conduction path as describedbelow.

The first lamp 38 is attached within the housing of the diagnostic tool1 at one end to the wire connection 51 and at the other end to the wireconnection 55. The second lamp 39 is attached at its two ends to thewire connections 51 and 54. The third lamp 40 is attached at its twoends to the wire connections 52 and 55. The fourth lamp 41 is attachedat its two ends to the wire connections 53 and 55.

In this manner, the first lamp 38 indicates that power is available fromthe fuse 35 within the conduction path if the lamp 38 is on, and theopposite if the lamp 38 is off. The second lamp 39 indicates that powerflows from through the fuse 35 and through the contacts 27 of theoverload protection block 29 when the lamp 39 is on. The third lamp 40and the fourth lamp 41 indicate when power is available at therespective ends of the seal-in 31 contact when the lamp attached to thatparticular end is on.

If power is available to the first end of the seal-in contact 31connected between stop switch 30 and the start switch 33 but is notavailable at the second end thereof connected between the start switch33 and the motor relay coil 11, then the electric motor 13 is ready tobe run assuming that the overload block contacts 27 are all closed. Inthis instance, the first three lamps 38, 39, and 40 would be on and thelamp 41 would be off since power is not available to the second end ofthe seal-in contact 31. However, if one of the overload block contacts27 were open in this instance than the second lamp 39 would not be onfor the reasons described above; therefore, the first lamp 38 and thethird lamp 40 would be on indicating that, if the overload protectionblock were reset, the machinery would be ready to run.

If the first lamp 38 is on indicating that power is available from thefuse 35 and the second lamp 39 is on indicating that the overload blockcontacts 27 are all closed, but the third and fourth lamps 40 and 41 areboth off, than no power is available to the first or second ends of theseal-in contact 31. In this instance, if the operator were to press thestart switch 33, the electric motor 13 will not start. In this instance,since power is available to the fuse 35, but does not reach the firstend of the seal-in contact 31 and the start switch 33, than either theauxiliary shut-down switch 19 is open or there is an open circuitbetween the fuse 35 and the seal-in contact 31.

As stated above, the diagnostic tool 1 of the present invention includesan alarm relay circuit 49 having three alarm relay wires connections 56,57, and 58. An alarm wire terminal block 59 is provided as shown in FIG.4. Two alarm relay contacts 61 and 62 are controlled by an alarm relaycoil 63. With the alarm relay coil 63 energized, the normally closedalarm relay contact 61 is opened and the normally open relay contact 62is closed. In this case, the common alarm relay wire 57 is connected toalarm relay wire 58 and not 56. If the alarm relay coil 63 isde-energized, than the common alarm relay wire 57 is connected to relaywire 56 and not 58. The alarm relay coil 63 is connected between wireconnections 53 and 55 within the housing of the diagnostic tool 1 and inparallel with the fourth lamp 41. Each of alarm relay wire connectionsare connected to an outside sensing device to indicate when lamp 41 ison, and therefore when the electric motor 13 is turned on.

The manner in which the diagnostic tool 1 of the present invention isinstalled to a control panel so as to be readily visible to an operatorwill now be described. As illustrated in FIG. 3, the diagnostic tool 1is attached to the door 43 of a control panel 3. As illustrated in FIG.4, the back end of the housing of the diagnostic tool 1 includes twothreaded screw stems extending out the back thereof having two screws 65and 67 attached thereto once screw stems are inserted through two holesdrilled through the control panel door 43. In this manner the diagnostictool 1 is secured to the outside of the control panel door 43. A thirdhole 69 drilled through the control panel door 43 allowing a cable 71having each of the wires 51-58 contained therein to enter into thecontrol panel 3. Fasteners 73 secure the cable 71 within the controlpanel 3. Each of the wires 51 and 58 are connected as indicated in FIG.4 so that the on-site diagnostic tool 1 can operate in the mannerdescribed above.

It is to be understood that the present invention is not limited to thesole embodiment described above, but encompasses any and all embodimentswithin the scope of the following claims. For example, more than onealarm contact relay circuit 49 may be provided to indicate various otherconditions of the control circuitry 5. Further, other types ofindicators may be used instead of the lamps 38, 39, 40, and 41, such aslight emitting diodes or audio tone generators having different soundingindications for each condition sensed by the diagnostic tool 1.

I claim:
 1. An on-site electric motor start-up diagnostic toolattachable to a motor start-up control panel, the panel including atleast one normally open drive contact for providing electrical power toan electric motor to drive the motor when the at least one normally opendrive contact is closed, a drive relay coil to close the at least onenormally open drive contact when energized as power passes from a firstend thereof through the drive relay coil to a second end thereof, anauxiliary power supply source for providing a voltage potential across apositive line and a negative line, at least one normally closed stopswitch connectable thereto, a load power line for providing power to theat least one normally closed stop switch, a first control wire forreceiving power from the at least one normally closed stop switchpassing therethrough from the load power line, a second control wireattached to the first end of the drive relay coil, a normally open startswitch receiving power from the first control wire and providing thatpower to the first end of the drive relay coil when closed, a normallyopen seal-in contact closed when the drive relay coil is energized, thenormally open seal-in contact receiving power from the first controlwire and providing that power to the first end of the drive relay coilwhen closed, at least one normally closed overload contact connected tothe second end of the drive relay coil and to the negative line forgrounding the second end of the drive relay coil when closed, and anoverload circuit including means for detecting an overload condition ofthe electric motor and means for opening the at least one overloadcontact when an overload condition of the electric motor is detectedthereby, said on-site electric motor start-up diagnostic toolcomprising:a first indicator for indicating the presence of the voltagepotential between the load power line and the negative line; a secondindicator for indicating the presence of the voltage potential betweenthe load power line and the second end of the drive relay coil; a thirdindicator for indicating the presence of the voltage potential betweenthe first control wire and the negative line; and a fourth indicator forindicating the presence of the voltage potential between the secondcontrol wire and the negative line.
 2. An on-site electric motorstart-up diagnostic tool as claimed in claim 1, further comprising:anormally open first alarm relay contact having a first end connected toa first indicator lead and a second end connected to a common lead; anormally closed second alarm relay contact having a first end connectedto said common lead and a second end connected to a second indicatorlead; an alarm relay coil for closing said normally open first alarmrelay contact and for opening said normally closed second alarm relaycontact when energized; and means for energizing said alarm relay coilwhenever said drive relay coil is energized.
 3. An on-site electricmotor start-up diagnostic tool as claimed in claim 1, wherein saidfirst, second, third, and fourth indicators include lamps containedwithin an outer housing connectable to an outside portion of said motorstart-up control panel.
 4. A motor start-up control panel comprising:atleast one normally open drive contact for providing electrical power toan electric motor to drive the motor when said at least one normallyopen drive contact is closed; a drive relay coil to close said at leastone normally open drive contact when energized as power passes from afirst end thereof through the drive relay coil to a second end thereof;an auxiliary power supply source for providing a voltage potentialacross a positive line and a negative line; at least one normally closedstop switch connectable thereto; a load power line providing power tothe at least one normally closed stop switch; a first control wire forreceiving power from the at least one normally closed stop switchpassing therethrough from the load power line; a second control wireattached to the first end of the drive relay coil; a normally open startswitch receiving power from the first control wire and providing thatpower to the first end of the drive relay coil when closed; a normallyopen seal-in contact closed when the drive relay coil is energized, thenormally open seal-in contact receiving power from the first controlwire and providing that power to the first end of the drive relay coilwhen closed; at least one normally closed overload contact connected tothe second end of the drive relay coil and to the negative power linefor grounding the second end of the drive relay coil when closed; anoverload circuit including means for detecting an overload condition ofthe electric motor and means for opening the at least one overloadcontact when an overload condition of the electric motor is detectedthereby; a first indicator for indicating the presence of the voltagepotential between the load power line and the negative line; a secondindicator for indicating the presence of the voltage potential betweenthe load power line and the second end of the drive relay coil; a thirdindicator for indicating the presence of the voltage potential betweenthe first control wire and the negative line; and a fourth indicator forindicating the presence of the voltage potential between the secondcontrol wire and the negative line.
 5. A motor start-up control panel asclaimed in claim 4, further comprising:a normally open first alarm relaycontact having a first end connected to a first indicator lead and asecond end connected to a common lead; a normally closed second alarmrelay contact having a first end connected to said common lead and asecond end connected to a second indicator lead; an alarm relay coil forclosing said normally open first alarm relay contact and for openingsaid normally closed second alarm relay contact when energized; andmeans for energizing said alarm relay coil whenever said drive relaycoil is energized.
 6. A motor start-up control panel as claimed in claim4, wherein said first, second, third, and fourth indicators includelamps contained within an outer housing connectable to an outsideportion of said motor start-up control panel.